Lathe-mandrel



Patented Aug.9, 1892.

J. H. MOGRAW.

LATHE MANDREL.

(No Model.)

INVENTOR.

4 ATTORN EYS 1' nnmus PETERS cc, PHDTO-LITHO., WASHINGTON o c WITNESSES:yfliwwm ggw UNITED, STATES PATENT OFFICE.

JOHN H. MOGRAW, OF OSWEGO, NEW YORK.

LATHE -MANDREL.

SPECIFICATION formingpart of Letters Patent No. 480,435, dated August 9,1892.

Application filed August 31, 1891. Serial No. 404,176. (No model.)

To all whom it may concern:

Be it known that I, JOHN H. MOGRAW, of Oswego, in the county of Oswegoand State of New York, have invented new and useful Improvements inLathe-Mandrels, of which the following, taken in connection with theaccompanying drawings, is a full, clear, and exact description.

This invention relates to the class of lathemandrels which areexpansible to fit different-sized holes or bores of the work to beoperated on.

The object of the invention is to provide an expausible mandrel whichshall be simple and comparatively inexpensive in construction andefficient and convenient in its operation.

To that end the invention consists, essentially, of an expanding mandrelcomprising a longitudinally-smooth tapering spindle provided withlongitudinal ribs and work-holding blocks grooved longitudinallyinternally and mounted thereby movably on the aforesaid ribs, ashereinafter more fully described, and set forth in the claim.

In the annexed drawings, Figure 1 is a side view of a lathe-mandrelembodying my invention. Fig. 2 is an end view of the same, and Fig. 3 isan end view illustrating amodification of my invention.

Similar letters of reference indicate corresponding parts.

P represents a smooth wedge-shaped or longitudiually-tapered spindle,which is provided with longitudinal ribs 1' r 7", preferably obtained byforming the said spindle angular in cross-section, either square, asshown in Fig. 2 of the drawings, ortriangular, as shown in Fig. 3, orother suitable shape. Upon the ribs or angles of the said spindle aremounted longitudinally movable the work-holding blocks a a a, which aresector-shaped in cross-section and provided with longitudinal grooves cc c internally, by which they ride on the aforesaid ribs or angles, andare thus restrained from moving laterally on the spindle P. Said sectorsare separate and detached from each other, and by means of a suitableadjustable clampsuch as a spring-steel band or other suitable elasticband I), embracing the sectorsthe latter are retained on the spindle Pwhen not in use. To confine said band in its position on the sectors, Iprovide the latter with a circumferential groove 6, in which the band isseated.

In using the described mandrel the spindle P, with the sectors to a a,is to be inserted into the bore or hole of the article to be secured tothe lathe, and then by driving the spindle from the large end thereofthe sectors a a a become spread apart from each other and radiallyoutward, so as to obtain a firm hold in the bore or hole. The taper ofthe spindle is so slight as to obviate the liability of the sectorsslipping accidentally on the spindle during the use of the mandrel. Toobtain greater range of adjustment of the mandrel, I form the sectors aa a with steps d d, by which the outer end portions of the sectors aremade larger in diameter than the adjacent inner end portions thereof,the difierent-sized portions of the sectors being used fordiiferentsized bores of the article or work to be held in the lathe.

What I claim as my invention is The combination, with the taperingspindle P, shaped angular in cross-section,of the sectors a a d,provided with longitudinal grooves c and riding thereby on the angles ofthe spindle and formed with steps d and circumferential groove 6, andthe elastic band b, seated in said groove and holding the sectorsyieldingly upon the spindle, substantially as de scribed and shown.

In testimony whereof I have hereunto signed my name this 25th day ofAugust, 1891.

JOHN H. MCGRAW'. [L. s]

Witnesses:

GEORGE HAY, PATRICK SHEEHY.

